Moving picture apparatus



June 19, 1 M. BOWMAN-MANIFOLD ET AL 1,963,485

MOVING PICTURE APPARATUS Filed July 9, 1930 5 Sheets-Sheet l Z. m mToes:

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MOVING PICTURE APPARATUS Filed July 9, 1950 5 Sheets-Sheet 2 //v V5 7058Mchaelflawman-llfmg'fold, WLLia/n Frazwr lid/tam,

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' MOVING PICTURE APPARATUS Filed July 9, 1930 5 Sheets-Sheet 5 AA BB' 5Sheets-Sheet 4 131,01. 6 flTTOE/VEK June 19, 19 M. BOWMAN-MANIFOLD ET ALMOVING PICTURE APPARATUS Filed July 9, 1950 June 19, 1934. M.BOWMAN-MANIFOLD ET AL 1,963,485

MOVING PICTURE APPARATUS Filed July 9, 1950 5 Sheets-Sheet 5 PatentedJune 19, 1934 UNITED STATES PATENT OFFICE MOVING PICTURE APPARATUS NewJersey Application July 9, 1930, Serial No. 466,626

In Great Britain July 10, 1929 14 Claims.

The present invention relates to apparatus for taking, projecting orviewing moving pictures. Such apparatus may be referred to generally ascinematographic apparatus.

For simplicity the word film will be used to designate any member,whether in the form of a long strip, a drum, a disc, or an endless loop,for example, upon wh ch a moving picture record is to be made, or fromwhich a moving picture image is to be projected or viewed.

It is an object of the present invention to provide improved apparatusfor projection or viewing in which stationary images, substantially freefrom optical distortion, may be produced from a continuously moving filmwithout the use of oscillating or intermittently moving parts.

Alternatively, it is an object of this invention to provide new means ofproducing moving picture negatives by photography on continuously movingfilm without the use of oscillating or intermlttently moving parts.

According to the present invention, the cinematographic apparatuscomprises one or more rotatably mounted mirrors disposed radially withrespect to their axis of rotaton, and means for moving a film (or thatpart thereof which is at any instant operative), or an image thereof,along a path adjacent to the mirror or mirrors at twice the angularspeed of said mirror or mirrors with respect to said axis.

The invention will be described by way of example with reference to theaccompanying drawings in which Fig. 1 is a diagram illustrating theprinciples of the invention,

Figs. 2 and 3 are diagrammatical views in elevation and plan,respectively, further illustrat'ng the principles of the invention,

Figs. 4, 5 and 6 are diagrams in front elevation, side elevation, andplan, respectively, illustrating further features of the'invention,

Figs. 7 and 8 show, somewhat diagrammatically, constructionalembodiments of the invention,

Fig. 9 is a plan view of the arrangement shown in Fig. 8.

Fig. 10 is a detail view to an enlarged scale of one of the mirrorswhich may be used in apparatus according to the invention, and

Fig. 11 shows, diagrammatically, further constructional embodiments ofthe invention.

In a simple form of the invention, illustrated in Fig. 1, a film 1 inthe form of a long, continuous strip, is passed around the outside of a65 drum 2 with angular velocity W, the film being passed round suitablerollers 3 disposed between the drum and wind-on and wind-off spoolsrespectively (which are not shown in this figure) so that the film is incontact with the drum over a considerable portion of its circumference.00 A plane mirror 4 is rotatably mounted within the drum and is arrangedsymmetrically with rei spect to the drum axis, so that the reflectingsurface contains the drum axis. The mirror axis is coincident with thedrum axis and the mirror is adapted to be rotated at half the angularspeed of the drum and in the same direction.

Light, indicated by lines C, from a suitable source external to the drumis passed through the film 1 and, when the mirror 4 is suitably situatedduring its rotation, is reflected by the mirror through a projectinglens, or objective 5, on to a screen. The periphery of the drum 2 is, ofcourse, either of transparent material or is provided with suitablewindows.

With this arrangement, a stationary virtual image of the particularframe A B of the travelling film which is at any time illuminated isformed upon the drum surface at A B. Light from this stationary imagewill pass into the so objective 5 and thence on to a screen, which isnot shown, when the mirror is in the above mentioned suitable positionof rotation.

If the mirror reflects on one side only, points on the film at adistance from one another equal to as twice the drum circumference willhave fixed images at the same point. With this arrangement, therefore,the successive frames would require a pitch (or distance from centre tocentre) equal to twice the drum circumference. In order to obtain thisin practice, either the length of each frame must be great in relationto the drum size (which would not usually be satisfactory) or arelatively large space would have to be left between successive framesof the same picture or episode. The space may of course, if desired, beused for one or more other pictures, in which case the total film lengthwould be u times that necessary for one episode but, on the other hand,one film would carry it different episodes.

To enable the frames successively projected to be arranged closertogether, as is customary, apparatus using a number of radially disposedplane mirrors is preferably used, as illustrated in Figs. 2' and 3. Inthis case, a number of mirrors 4 are arranged radially about the axis ofrotation of the film 1 between rollers 3. The mirrors, of which theremay be any convenient number, forty-eight being shown in this diagram,are

equally spaced and extend about four thirds of the length of a pictureframe from the inside of the drum circumference towards the axisthereof, so that a cylindrical space bounded by the envelope of theirinner edges is left within the mirrors. In order that every frame may beprojected in turn, the circumference of the circle in which the filmmoves must be equal to half the product of the number of mirrors and thedistance between successive frames. Other parts may be as alreadydescribed.

During a short are of its travel, the film 1 is illuminated from C, thesource being so arranged that the light, after passing through the film,falls obliquely on one of the radial mirrors and forms a stationaryvirtual image of the illuminated frame AB at A B on the drumcircumference. Each frame will form, in turn in a corresponding mirror,an image in the same position, while light from this image will passinto the cylindrical space within the mirrors. In order that this lightmay not be obstructed by any of the other mirrors, the back surface ofthe inner and outer edges of each mirror may be bevelled (as shown at '7in Fig. 10, the reflecting surface being indicated in this figure by d),and the direction of the light may be changed, for example, by means ofa fixed plane mirror 8 disposed within the cylindrical space at an angleof 45 to the axis. This stationary mirror will reflect light in adirection sensibly parallel to the axis. A projecting lens 5 is placedso that it receives light from the stationary mirror and forms a'finalreal image upon the screen. Alternatively, the projection lens 5 may beplaced between the radial mirrors 4 and the plane mirror 8.

The mirrors 4 may be formed of stainless steel.

It will be seen that if the length of film illuminated at one time issmall compared to the radius of the circle containing the outer edges ofthe mirror, then a close approximation to the above result may beobtained by moving the film along a path which is not circular and mayeven be linear. In the latter case, the speed of the film must be suchthat the angular velocity of a point on it is twice that of the mirror.

The obliquity of the virtual image formed by the radial plane reflectingsurfaces may be avoided or reduced and thus substantially evenlyfocussed final images may be formed, after reflection from the radialmirrors, in a plane normal to the reflected beam, by replacing themoving film by a rotating series of images of the successive frames, asshown in Figs. 4, 5 and 6. In this arrangement, two drums (of which onlyportions are shown) are used rotating about a common axis one above theother (Fig. 6). The lower drum 2 upon which the film 1 rotates isprovided with a number of identical optical systems of which only one isshown in the diagram, the angular pitch of these optical systems beingequal to the angular pitch of the frames on the film. The opticalsystems may be arranged to form images in any desired position, andthese images, in any case, rotate in the same direction and with thesame angular velocity as the film. A system of radial mirrors, asdescribed in the last example, of which only one indicated by 4 isshown, rotate within the upper drum 9 in the same direction and withhalf the angular velocity of the film or its image. Each optical systemattached to the film drum comprises a cylindrical lens 10 adapted toremove the curvature of the image produced from the curved film, amirror 11 inclined relatively to the axis and also relatively to thetangent to the drum at the centre of the active frame, and a lens 12.Each system forms a moving image of a frame at A B and this image servesas the object for the system of radial mirrors disposed within the upperdrum and replaces the actual film image described in the previousexamples. A stationary image A B of the object A B is formed in theradial mirrors 4. The inclined mirrors 11 upon the film drum serve tothrow the light from a source 13, arranged outside the drum, afterpassing through the film 1 and the cylindrical lens 10, in a directionoblique to the axis of the drum so that it falls obliquely upon one ofthe radial mirrors 4. Light from the image A B formed by the radialmirrors 4 passes, again in a direction oblique to the drum axis, througha suitable stationary projecting lens 5.

In a modification of the arrangement last described, instead of theoptical systems being rotated with the film, a single fixed opticalsystem may be used which will also produce images which move in the samedirection and with the same angular velocity as the film, but the systemmust not contain a plane mirror. The radial mirrors are thereforerotated as before in the same direction as the images and at half theirangular speed.

Any stationary plane mirror in the optical system reverses the directionof motion of the images, and, where such a mirror is used, the radialmirrors must be rotated in the opposite irection to the film.

The obliquity of the stationary images may be corrected more simply byinserting a prism of certain thickness and face angles between the filmand projecting lens in such a manner that the stationary images areformed in a plane which is normal to the direction of viewing.

Fig. 7 shows the general arrangement of apparatus in one form of theinvention. The film l is driven by the sprocket l4 and travels from thespool 15 by rollers 3, over the stationary cylindrical guide drum 2,past a single gate aperture 16, and into a spool casing 17. Thecircumference of the cylindrical guide drum is thirty frames in length.A spring loaded pad 18 presses the film against the guide drum 2. Theroller 3 shown in the upper right hand corner of Fig. 7 is adjustableand is used to alter the length of film between the driving sprocket andthe gate aperture. By this means, a complete picture can be broughtopposite the gate aperture when the radial mirrors are in the correctposition for reflecting a complete pcture, the film being therebycorrectly framed. The film is illuminated as it passes the gate apertureby light from a source in the lamp housing 20 containing a condensinglens 21. sixty stainless steel mirrors 4, is rotated, by means ofsuitable gearing, concentric with and inside the cylindrical guide athalf the angular speed of the film. At the gate, the reflecting faces ofthe mirrors are upwards and reflect light which passes onto them fromthe film onto the projecting optical system. This system consists of alens 5 with its axis horizontal, a plane m rror 8 which stands in avertical plane inclined at 45 to the lens axis, and an obliquitycorrecting prism (not shown, but which is placed between the lens 5 andmirrors 4). The combined movements of the film and disc of mirrors issuch that the light received by the projecting lens 5 comes normallyfrom a stationary virtual image of the illumi- A disc 6, on which aresupported nated part of the film. The final image is formed on avertical screen as usual.

In a modification (illustrated in Fig. 11) of the above describedapparatus,.the drum 2, which serves as guide for the film (which is notshown in this figure), is adapted to be rotated at the same speed as thefilm. To obtain this, the said drum carries on its circumference tworows of sprocket teeth 28 which engage perforations in the film thusserving to drive the film and avoiding the necessity of a separatedriving sprocket In this case, the drum has a series of gate apertures16 cut in it, the angular pitch of these apertures being the same as theangular pitch of the frames on the film.

The radial mirrors 4 are attached to the inner surface of a hollowspindle 29, and the obliquity correcting prism 26 (with which iscombined a reflecting surface 8) and the projecting lens 5 are mountedwithin the cylindrical space formed by the inner edges of the radialmirrors, the final beam of light thus emerging from the apparatus in adirection sensibly parallel to the axis of the spindle. The guide drum2, which carries the fllm, is mounted upon or made an integral part of amember 30 which is mounted coaxially with and around the hollow spindle29. By means of suitable gearing 31, the spindle 29,carrying the radialmirrors, is made to rotate with angular velocity and the outer member30, carrying the film, is made to rotate in the same direction withangular velocity W. Light, emanating from within a housing 20, passesthrough the moving film and one of the apertures 16 and falls obliquelyupon one of the radial mirrors 4. Since the radial mirrors move withhalf the angular velocity of the film, a stationary virtual image of thefllm is formed on the drum circumference and this image is projectedthrough the prism 26 and lens 5 on to a viewing screen.

Figs. 8 and 9 illustrate another type of projector in which the film maybe illuminated by transmitted light or in which pictures upon an opaquecarrier, such as a paper strip, may be' illuminated by reflected light.In these figures, two alternative positions for a lamp housingcontaining a suitable source of light are shown at 20 and 22. If film isto be illuminated, light from the housing at 20 (shown by the dottedlines) is reflected from the plane mirror 23 through the film; if paperstrip is to be illuminated, light from the housing at 22 falls directlyon to the inner face of the paper. The film or paper strip is wound offthe spool 15, along rollers 3, over the guide 2, and into the spool 27,and it may be rewound along the track over the rollers 24. The screw 25is used for adjusting the position of the lens 5, and 26 is theobliquity correcting prism. The disc 6 carrying the radial mirrors ismounted on a hollow spindle, and mirror 8 reflects the emergent beam ina direction sensibly parallel to the axis of said spindle, the finalimage being formed on a vertical screen which is perpendicular to saidaxis.

There are many possible modifications of the invention other than thoseherein described. For example, the film may be run inside the radialmirror system instead of outside it. Furthermore, it will be clear thatthe axis about which the radial mirrors and the film or image thereofrotate, which has been assumed, in the above examples, to be-horizontal,may be in any direction.

Although the invention has been described with particular reference toprojection, it will be evident that similar apparatus can be used forviewing or as a camera.

When the invention is used in a camera it is necessary to restrict thegate aperture to half the distance between successive frames to avoidoverlapping of images.

We claim:

1. In a cinematographic apparatus, the combination of a drum, aplurality of reflectors positioned within said drum in equally spacedrelation and extending radially therein a distance short of the radiusthereof, said reflectors all having their respective reflecting surfacesfacing in the same direction, means for rotating said reflectors at apredetermined speed, and means for moving the film over said drum at aspeed different than but complemental to the speed of said reflectors.

2. a cinematographic apparatus, the combination of a drum, a pluralityof reflectors positioned within said drum in close proximity to theinner wall thereof and in equally spaced relation, said reflectorsextending radially within said drum a distance short of the radiusthereof and having their respective reflecting surfaces facing in thesame direction, means for rotating said reflectors at a predeterminedspeed, and means for moving the film over said drum at a speed differentthan but complemental to the speed of said reflectors.

3. In a cinematographic apparatus, the com-. bination with a drum and afilm movable thereover and having a plurality of substantially uni.

formly positioned picture frames thereon, of a rotatably mountedsupporting member concentric with said drum, and a plurality ofreflectors mounted on said member in equally spaced relation andextending within said drum adjacent the inner wall thereof and in aradial direction, the circumference of the circle in which said filmmoves being numerically equal to half the product of the number ofreflectors on said member and the distance between successive frames onsaid film.

4. In a cinematographic apparatus, the combination of a fixed drumhaving an aperture in the wall thereof and being openat its ends, arotatably mounted supporting member adjacent one end of said drum andconcentric therewith, and a plurality of reflectors mounted on saidmember in equally spaced relation and extending within said drumadjacent the inner wall thereof and in a radial direction therein, theouter wall of said drum being adapted to serve as a guide for thepassage of a film thereover,

5. In a cinematographic apparatus, the combination of a fixed drumhaving an aperture in the wall thereof and being open at its ends, arotatably mounted supporting member adjacent one end of said drum andconcentric therewith, a plurality of reflectors mounted on said memberin equally spaced relation and extending within said drum adjacent theinner wall thereof and in a radial direction therein, the outer wall ofsaid drum being adapted to serve as a guide for the passage of afilmthereover, means for rotating said member, and means for feeding saidfilm over said drum.

6. In a cinematographic apparatus, the combination of a rotatablymounted drum open at its ends, a plurality of apertures in the wall ofsaid drum, a rotatably mounted supporting member adjacent one end ofsaiddrum and concentric therewith, a plurality of reflectors mounted onsaid member in equally spaced relation and extending within said drumadjacent the inner wall thereof and in a radial direction therein, meansfor rotating said member whereby said reflectors are rotated therewith,and means for rotating said drum at a speed different than butcomplemental to the speed of said reflectors.

'I. In a cinematographic apparatus, the combination of a rotatablymounted drum open at its ends, a plurality of apertures in the wall ofsaid drum, means on said drum for advancing a film therewith inregistration with said apertures, a rotatably mounted supporting memberadjacent one end of said drum and concentric therewith, a plurality ofreflectors mounted on said member in equally spaced relation andextending within said drum adjacent the inner wall thereof and in aradial direction therein, means for retating said member whereby saidreflectors are rotated therewith, and means for rotating said drum at aspeed different than but complemental to the speed of said reflectors.

8. In a cinematographic apparatus, the combination of a drum and aplurality of reflectors mounted within said drum adjacent the inner wallthereof and extending radially therein a distance short of the radius ofsaid drum, whereby a space is provided concentric with said drum anddefined by the ends of said reflectors removed from said wall, saidreflectors being equally spaced from each other and having their respective reflecting surfaces facing in the same direction.

9. In a cinematographic apparatus, the combination of a drum, aplurality of reflectors mounted within said drum adjacent the inner wallthereof and extending radially therein a distance short of the radius ofsaid drum, whereby a space is provided concentric with said drum anddefined by the ends of said reflectors removed from said wall, saidreflectors being equally spaced from each other and having theirrespective reflecting surfaces facing in the same direction, and a fixedoptical system within said space.

10. In a cinematographic apparatus, the combination of a drum, aplurality of reflectors mounted within said drum adjacent the inner wallthereof and extending radially therein, said reflectors being equallyspaced from each other and having their respective reflecting surfacesfacing in the same direction, a second drum spaced laterally from butconcentric with said first drum, a film movable over said second drum,and optical means associated with said second drum for projecting animage of said film onto said radial reflectors.

11. In a cinematographic apparatus, the combination of a drum, aplurality of reflectors mounted within said drum adjacent the inner wallthereof and extending radially therein, said reflectors being equallyspaced from each other and having their respective reflecting surfacesfacing inthe same direction, a second drum spaced laterally from butconcentric with said first drum, said second drum being rotatablymounted, means for rotating said drum, a film movable over said seconddrum, and a plurality of optical devices associated with said seconddrum for projecting an image of said film onto said radial reflectors assaid second drum is rotated.

12. Apparatus according to claim 10 wherein said optical means and saidreflectors are so related that an image is projected by said opticalmeans onto said reflectors in a direction such that a substantiallyevenly focused final image is formed, after reflection from said radialreflectors, in a plane normal to the reflected beam.

13. In a cinematographic apparatus, the combination of a drum having anaperture in the wall thereof and being open at its ends, a rotatablymounted supporting member adjacent one end of said drum and concentrictherewith, a plurality of reflectors mounted on said memher in equallyspaced relation and extending within said drum adjacent the inner wallthereof in a radial direction therein a distance short of the radius ofsaid drum, whereby a space is provided concentric with said drum, a filmmovable over said drum, means for feeding said film over said drum, asource of illumination in alignment with said drum aperture, and opticalmeans located within said space for directing a light beam from saidsource out of said drum through the open end thereof removed from saidsupporting member.

14. In a cinematographic apparatus, the combination of a drum having anaperture in the wall thereof and being open at its ends, a rotatablymounted supporting member adjacent one end of said drum and concentrictherewith, a plurality of reflectors mounted on said member in equallyspaced relation and extending within said drum adjacent the inner wallthereof in a radial direction therein a distance short of the radius ofsaid drum, whereby a space is provided concentric with said drum, a filmmovable over said drum, means for feeding said film over said drum, asource of ilumination in alignment with said drum aperture, and opticalmeans located within said space for directing a light beam from saidsource out of said drum through the open end thereof removed from saidsupporting member and in a direction substantially parallel to the axisof rotation of said radial reflectors.

MICHAEL BOWMAN-MANIFOLD. WILLIAM FRANCIS TEDHAM.

